The present invention pertains to a simplified water recycling system for use in dental operatories in which evacuation of fluid from a patient's mouth which includes impurities, such as saliva, tooth and metal chips, and the like, occur by means of vacuum pumps having liquid seals by which the pumps are primed and a residual amount of liquid is maintained in the pumps at all times for insuring adequate sealing at initial startup. A system comprising the present invention offers substantial simplification over systems currently in use, as well as certain advantages thereover described in detail hereinafter.
Liquid seal vacuum pumps have been employed in dental evacuating systems, particularly since the introduction of discharging flushing water into a patient's mouth while certain chipping and grinding operations are performed by a dentist, and therefore, it has been necessary to develop so-called high volume evacuating systems to constantly withdraw the flushing water, saliva and impurities from the oral cavity of a patient. Typical examples of such systems used heretofore are illustrated in prior U.S. Pat. Nos. 3,482,313 to Stram, dated Dec. 9, 1969, 3,964,112 to Plowman, dated June 22, 1976, and 4,245,989 to Folkenroth et al, dated Jan. 20, 1981. In the system of the Stram patent, fresh water is constantly introduced approximately to the extent of two hundred forty gallons per normal working day, and this water, after passing through the pump, engages a liquid and air separator and the water is discharged entirely to a drain.
In the systems of the Plowman and Folkenroth et al patents attempts to conserve water consumption are disclosed, particularly the water received from the cuspidors of dental operatories, by the Plowman patent filtering the contaminated water and recirculating at least part of it through the liquid seal pumps to maintain the same in primed condition. The Folkenroth et al patent recirculates contaminated water to the pumps to effect the seal thereof and effects certain economies in water consumption. However, these systems are relatively extensive and complex, in contrast to the far more simple system of the present invention which is directed to water conservation, but in which system no contaminated water passes through control valves which conceivably could remain at least partially open in the event contaminated water passed through the same and some of the contamination became lodged between the valve member and seat of the control valve.